"Forward an email" form should not impersonate the constituent

Dropping the action.forward token in an email generates a link through which contacts may forward messages to their friends. This form sends mail with the FROM header sent to the constituent's email address. This is poor practice, is likely to be treated as spam, and depending on the SMTP provider may be rejected outright.

Proposal is that the message come from the domain address and mention the sending user, e.g., "John Smith (john.smith458@example.org) has forwarded this message to you."